Research On Key Technologies Of Integrated Photonic Beamforming System

Millimeter-wave communication is a research hotspot of 5G mobile communication technology.The application of beamforming technology in massive MIMO(multipleinput multiple-output)antenna systems can improve the serious path loss problem of millimeter-wave communications.With the development of integrated photonics,researchers began to integrate the optical true time delay beamforming system in a siliconbased optoelectronic hybrid chip.This type of chip greatly reduces the volume of the optical true time-delay beamforming system,the integrated photonic technology will help the 5G mobile communication system to become miniaturized.The research focus of this paper is to combine integrated photonic waveguide technology and optical true delay beamforming technology to design an integrated photonic waveguide beamforming system for the field of 5G millimeter-wave communications.The main content and innovations of this paper are as follows:(1)This article proposed an integrated photonic waveguide beamforming system for28 GHz millimeter-wave signals.The optical beamforming network is composed of multiple waveguide Bragg gratings in the system.By adjusting the operation wavelength of the optical signal in the range of 1513.17 nm to 1595.71 nm,a time delay difference of-15.46 ps to 15.46 ps can be formed between the adjacent photonic waveguide time delay lines,and the beam of 4-elements linear array antenna can be scanned in a horizontal range of-60° to 60°,and the beam pointing angle interval is 15°.(2)This article discusses the research ideas and workflow of designing and analyzing photonic waveguide devices using specialized simulation software.This article uses Lumerical simulation software to complete the design,analysis,and optimization of a variety of photonic waveguide devices.First,the refractive index distribution of the SOI straight waveguide and the electric field distribution of the internal optical signal are analyzed,and the group index and the effective refractive index of the SOI straight waveguide are calculated.Secondly,the waveguide Y-branch is designed,and the 1×4waveguide optical beam splitter is designed by using the cascaded Y-branch waveguide structure.Next,9 waveguide Bragg gratings with different period lengths are designed for the photonic waveguide time delay line,and these gratings are used to form a waveguide optical beamforming network.Finally,a lot of detailed performance tests are performed on the above devices using simulation software.(3)In this paper,the PAS toolbox in MATLAB software is used to analyze the performance of the integrated photonic waveguide beamforming system,and calculates the radiation pattern of the 28 GHz millimeter-wave signal in the system.The beamforming ability of the system for 27GHz?29GHz millimeter-wave signals is simulated.According to the simulation results,it is proved that the operation bandwidth of millimeter-wave signals in the system can exceed 850 MHz,which meets the technical requirements of 5G mobile communication systems.